For the Beef Patties:

• 1 pound ground beef (80% lean)
• 1 large egg, lightly beaten
• 2 tablespoons grated Parmesan cheese
• 2 tablespoons breadcrumbs (preferably panko)
• 1 teaspoon Worcestershire sauce
• 1 teaspoon tomato ketchup
• 1 teaspoon dried oregano
• 1/4 teaspoon garlic powder
• Salt and black pepper to taste
• 2 tablespoons vegetable oil (for searing)

For the Mushroom Gravy:

• 1 large onion, thinly sliced
• 12 oz cremini or button mushrooms, sliced
• 1 tablespoon tomato paste
• 1½ teaspoons Worcestershire sauce
• 1 to 1¼ cups beef broth
• 2 tablespoons half-and-half or heavy cream
• 1 teaspoon onion powder
• 1/2 teaspoon garlic powder
• Optional: 1 tablespoon cornstarch mixed with 1/4 cup water for slurry
• Fresh chopped parsley for garnish